The Gregory Standard, the 4Cs
The Gregory Standard, the 4Cs
The meticulous process of individually selecting each diamond by eye ensures that Gregory Jewellers is only acquiring the most beautiful diamonds.
26 May 2020 5 minute read


More than any other characteristics, the precision of cut and overall proportion of a diamond when being cut from a rough diamond, ultimately determines the brilliance of the diamond.

A polished diamond’s brilliance lies in its complex relationship with light – how light reflects off the facets, how much enters the diamond and what amount of light returns to your eye.

The proportion of each individual diamond directly affects its brilliance and appeal. Diamonds with excellent proportions, symmetry and polish optimise their interaction with light. Often diamonds are cut to retain weight rather than excellent proportion, as this may sometimes yield a slightly higher price as the expense of quality.


The Gregory Standard ensures all our certified diamonds are accurately categorised according to their proportions, symmetry, and polish which ultimately determines their brilliance.



The colour of a diamond is an important characteristic when determining a diamonds value. Generally the less colour, the higher the value. The exception to this is fancy-colour diamonds, such as pinks and blues, which lie outside this colour range.


Diamonds are normally characterised by their lack of colour, and using a set of authenticated master diamonds to compare against, each diamond is given a grade using the English alphabet from D (colourless) to Z (most saturated colour).


The untrained eye is incapable of making assessments that dramatically affect a diamond’s value.



The weight of a diamond is measured in carats.

It is important to remember that carat weight alone does not determine a diamond’s value. Diamonds of equal weight can vary widely in price because of difference in cut, proportion, colour, clarity & other characteristics. Two diamonds that weigh the same can in fact have completely different measurements.



Because diamonds are formed deep within the earth’s core, under extreme heat and pressure, they often contain unique birthmarks, either internal inclusions or external blemishes.

Virtually all diamonds have naturally occurring inclusions or blemishes – the size, position and type of these inclusions have a direct effect on a diamond’s beauty and value.

The Gregory standard ensures that each diamond’s clarity is assessed by our team of diamond buyers before it is purchased. This meticulous process of selecting each diamond by eye refines each clarity grade, allowing us the opportunity to source the best each grade has to offer. We often reject diamonds with flaws accepted by others, including laser drill holes and diamonds with a high concentration of natt inclusions.


Two diamonds which may have the same clarity grade on a diamond certificate can appear very different when viewed in person. One cannot rely on a diamond’s certified characteristics alone.

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